Ike, an intense hurricane, bound for Gulf. Updated.

1 p.m. UPDATE: This afternoon’s model runs have started to come out and the most favored solution is a strike on the upper Texas coast. Be advised that computer models have five-day errors that regularly exceed 400 miles, so it’s not time to panic. But within the next five to six days Texas could be facing a serious hurricane.

Summarizing the major models:

The UKMET, European and GFS models all bring a major hurricane to the upper Texas coast about six days from now.

The HWRF model prefers a solution that brings a relatively weaker storm toward the southeastern Louisiana coast. The NOGAPS model has a similar track.

There are no clear trends, here. The models have continued to focus on an area between Corpus Christi and the Louisiana-Mississippi border.

ORIGINAL ENTRY: Hurricane Ike remains a powerful Category 4 hurricane this morning as it approaches Cuba and will likely reach the island within a day or so.

The big question, for our purposes, is where Ike’s likely to go once in the Gulf. The official forecast has a large cone of uncertainty, and as we’re still probably at least five days from landfall it’s a difficult question to answer.

The possibilities range from northern Mexico to the Florida panhandle. From Corpus Christi to the Louisiana-Mississippi border remain the likeliest landfall locations.

It should be noted that some of the models now forecast less time over Cuba, which means the storm could weaken less than anticipated over the island, bringing a more powerful hurricane into the Gulf.

Because the island is so narrow it’s difficult to forecast the amount of interaction with Cuba even one to three days in advance. What we can begin to talk about are conditions in the Gulf of Mexico when Ike reaches it in a couple of days.

WARM GULF WATERS

A common question is whether Hurricane Gustav stirred up enough deeper, cool water to have a significant effect on sea surface temperatures in the Gulf of Mexico. Here’s a map of such temperatures just before Gustav reached the Gulf:

NOAA/AOML

Gulf sea surface temperatures on Aug. 30

Recall that it takes waters of about 80 degrees Fahrenheit (or 27 Celsius) to sustain and strengthen hurricanes. Now let’s look at a graphic showing the Gulf temperatures now:

NOAA/AOML

Gulf sea surface temperatures on Friday

Gustav clearly had a moderate cooling effect on the seas, but nothing that should particulary inhibit the intensification of a hurricane. Moreover, the tropical cyclone heat potential, shown below, is virtually unchanged since the pre-Gustav days.

NOAA/AOML

And as can be seen from the forecast track above, there’s a reasonable chance a storm coming off Cuba would pass over the Loop Current, allowing for significant and rapid re-intensification.

But wait, didn’t forecasters say that about Hurricane Gustav? Yes, the forecasters predicted that. What they didn’t foresee was slightly higher than anticipated shear as Gustav crossed Cuba, which caused the storm’s vortex — it’s central tower — to become off-centered.

This could also happen with Ike, but we just cannot know at this time. Wind shear isn’t forecast to be a significant impediment in three to five days time, but such forecasts aren’t wholly reliable.

There are other potential mitigating factors in the Gulf, too. As noted by the forecasters at the Houston/Galveston office of the National Weather Service, one is the potential to encounter dry air along the Gulf Coast like that which has kept our recent mornings most pleasant. An incursion of dry air could also disrupt Ike’s circulation.

But these caveats aside, the bottom line is that Ike remains a dangerous storm and legitimate threat to Texas. It also has the potential to slam the areas just affected by Gustav. We must watch it closely this week.